Rotors of rotary engines



May'5, 1964 1.. PERAS ROTORS 0F ROTARY ENGINES Filed Dec. 27, 1961 2Sheets-Sheet 1 v INVENTOR 1.4a fen Pehs Rrronusvs May 5, 1964 L. PERASROTORS 0F ROTARY ENGINES 2 Sheets-Sheet 2 Filed Dec. 2'7, 1961 m P T. .nw W. W w om HTTORNEIS I United States Patent 3,131,679 ROTORS 0F RUEARYENGHJES Lucien Pras, Biiiancourt, France, assignor to Regie Nationaledes Usines Renault, Billancourt, France Filed Dec. 27, 1%1, Ser. No.162,540 Claims priority, application France Earn. 18, 1961 6 Ciairns.(Ci. 123-8) This invention relates to rotary engines in general and moreparticularly to the rotors of such engines.

It is known that the component elements of rotary engines and moreparticularly the rotors subjected to a heat flux and to mechanicalstress as a result of the explosion or fuel combustion, so that specificcares must be exerted with a view to ensure their proper cooling.

To this end, oil may be circulated through the rotor.

This invention is concerned with specific arrangements of the means forcirculating lubricating and cooling oil in order to ensure the bestpossible protection of the most exposed portions of the rotor, thesearrangements being described hereinafter with specific reference to arotary engine comprising a stator divided into five working chambers anda four-lobed rotor.

In general, the oil circulates in a closed circuit of well known typecomprising a cooling radiator and a pressure pump, so that it isdelivered in its cooled condition to the front centre of therotor-carrying crankshaft, this oil being forced through the rotor alonga path to be defined presently and flowing to the rear end of thecrankshaft before finally leaving the engine and returning to thecooling device.

In a rotary engine of the type comprising five working chambers, in thestator and four lobes in the rotor, five explosions take place during ahalf-revolution of the rotor.

It is known that in an engine of this type the number of chambers isnecessarily an odd number; in the example considered herein this numberis five; since the stator and rotor act like two toothed wheels having aone-tooth difference with each other, and since on the other hand thefiring order is 1352-4 and so forth, as in any four-stroke radialengine, it is obvious that only two lobes are affected by the engineexplosions, so that these chambers are subjected to high thermal andmechanical stress while the other two lobes are less exposed to fatigueas a consequence of engine operation.

According to a specific arrangement provided by this invention, thecooled oil separates within the rotor into two circuits comprising eachtwo radial ducts, that is, an inlet duct and an outlet duct, and aperipheral duct, each radial inlet duct leading respectively to one ofthe lobes subjected to the explosions, that is, substantially to one ofthe two most exposed zones of the rotor.

Then, the oil circulates in the peripheral ducts so as to contact thecoldest portions which are the less exposed to the engine cycle beforereturning to the crankshaft through the second radial duct. Thus, theefficiency of this oil circulation will be clearly understood; thepurpose is to firstly protect and cool the most exposed zone of therotor in order to preserve as much as possible all its metallurgicalproperties necessary for ensuring a long useful life of the rotor, andsecondly to thermally equalize or even reheat the other portions of therotor.

Moreover, the oil ducts formed through the rotor are designed with aview to reduce to a minimum their crosssectional area in order tomaintain the oil flow rate at a value adapted to ensure a satisfactorycooling and reduce the quantity of oil which, in a rotor revolvingeccentrically, is subjected to variable positive and negative accelerations tending to interfere with the rotor rotation.

The invention will now be described with reference to the accompanyingdrawings illustrating diagrammatically 3,l3l,579 Patented May 5, 196% byway of example a typical embodiment of this invention. In the drawings:

FIG. 1 is a longitudinal axial section showing a rotary engineconstructed according to the teachings of this invention;

FIG. 2 is a cross-section taken upon the line 11-11 of FIG. 1 to showthe engine stator and rotor, and the oil circulation;

FIG. 3 is a section taken across the crankshaft at position III-III ofFIG. 1, to show the oil return path therein; arid FIGS. 4, 5, 6 and 7are sections showing on a smaller scale the stator and rotorrelationship during the different engine strokes, in order to afford aclearer understanding of this invention.

Referring to the drawings, FIG. 1 illustrates a rotary engine of thetype comprising five working chambers in the stator and four lobes inthe rotor; 21 is the stator ring, 22, 23 the stator flanges, 24 therotor, 25 the crankshaft, 26, 26 the internally-toothed guide annulirigid with the stator and 27, 27' the rotor driving gears and a sleeve40.

As already explained, the engine rotor is cooled by an oil circuitcomprising a radiator 50, an oil pump 51 and pipe lines 52 disposedexternally of the engine.

This invention is concerned more particularly with the internal oilcircuit of the engine which comprises on the flange 23 an inlet fitting28 communicating with a longitudinal duct 29 formed along the crankshaftaxis and communicating through lateral passages 36 with the rotormounted on the crankshaft eccentric. Then the oil circulates through therotor along a specific path to be described presently; the oil finallyescapes from the rotor through radial holes 41, 42, 43, 44 and 45 (FIG.3) leading into the rear axial duct 46 of the crankshaft, and isdischarged through the fitting 47 of flange 22. As shown in FIG. 2, thecrankshaft revolves in the clockwise direction and the rotor in theopposite direction; the firing order of the chambers is 13--524, theworking chambers 1, 2, 3, 4 and 5 being numbered in the direction ofrotation of the crankshaft.

The working chamber 1 is at firing point (FIG. 2) when the lobe 11 ofthe rotor fills nearly completely the working chamber 1, except thecombustion chamber 53 shown in dotted lines.

Now the rotor and the oil circuit through this rotor will be describedmore in detail.

The rotor is of the double wall type, as shown at 24, 24, so as to leavea constant-width annular space therebetween. This double wall structureforms lobes 11, 12, 13 and 14.

This annular chamber is closed also on the sides and connected throughhollow radial arms 38, 39 forming as many oil passages to the hub 33.These arms are disposed along a common diameter and open into theannular chamber at the joint between adjacent lobes. Each arm 38, 39 isdivided into two halves by an intermediate longitudinal partitionextending from the hub 33 to the outer wall 24. Moreover, reinforcingdistance-pieces or ribs may also be provided notably between the hub andthe other joints between adjacent lobes, as shown at 48, 48. The oilflowing from the passages 39 formed in the eccentric penetrates into therotor through the first radial duct 34 and circulates in the peripheralpassage 36 which faces the combustion chamber and the working chamber 1,thus supplying cooled oil to the stressed zone of the rotor. This oil isgradually heated as it flows along the peripheral duct 36 wherein onefraction of the heat carried along by the oil propagates in the lobe 14.Thus, it will be seen that the oil tends the cool lobe 11 and heat lobe14, so that thermal conditions are substantially equalized.

Subsequent to the explosion in chamber 1, the cooled oil still suppliedthrough the peripheral duct 36 cools the end portion of lobe 11 and theinitial portion of lobe 14 moving past the working chamber 1 in whichthe gas expansion takes place.

Simultaneously, the oil cooled in radiator 50 is delivered through theother inlet duct 35 located shortly before the lobe 13 diametrallyopposite to lobe 11. This oil flows through the peripheral duct 37 andcools the lobe 13 so as to place it in the best thermal conditions andtherefore in the best mechanical conditions, for as shown in FIG. 4,after lobe 11 it is the opposite lobe 13 that has to withstand theexplosion taking place in working chamber 3 after the rotor has revolvedthrough one-tenth of a revolution.

Then the Working chamber 5, FIG. 5, is at firing point and the explosiontakes place in this chamber in front of the lobe 11 receiving again theexplosion after another rotation through one-tenth of a revolution, thatis, 36. In FIG. 5 it will be seen that the cooling process is the sameas that just described.

After another 36-degree rotation of the rotor (FIG. 6) the workingchamber 2 is at firing point and the explosion takes place in thischamber in front of lobe 13 receiving another explosion. The radialpassage 35 and the peripheral duct 37 deliver cooled oil as before.

Then, as shown in FIG. 7, the firing point has moved to working chamber4 and the explosion takes place in this chamber in front of lobe 11,after another 36-dcgree rotation of the rotor. The cooled oil isdelivered through duct 34 and circulates in the peripheral circuitelement 36.

Thus, the explosions took place successively in the five workingchambers in the predetermined order 1--35--2-4 and each time the rotorrevolved through 36 degrees or one-tenth of a revolution to alternatelypresent the lobe 11 and lobe 13 in each chamber at each explosion, whileexcluding lobes 12 and 14. Thus, it will be seen that the rotor of thisinvention provides for the circulation of cooling oil a particularlyadvantageous arrangement permitting a rational cooling of the enginewhich is attended by a thermal balance whereby the useful life of theengine and notably of the rotor is increased considerably.

Although this invention has been described with reference to a singleembodiment of the essential features thereof, it will be readilyunderstood by anybody conversant with the art that many modificationsand variations may be brought thereto without departing from the spiritand scope of the invention as set forth in the appended claims.

I claim:

1. A rotary engine comprising stator means having a plurality ofchambers disposed therearound and internally thereof, eccentric meansdisposed within said stator means and coaxially therewith, rotor meanshaving a plurality of lobes rotatably mounted on said eccentric means,said lobes cooperating with said chambers as said rotor means rotates;said rotor means including an outer wall and an inner wall defining asubstantially constant width annular space therebetween, a hub memberengaging said eccentric means, arms extending from said hub member tosaid walls thereby forming with said annular space two continuouspassages; inlet means disposed in said stator means and said eccentricmeans for supplying cooling fluid thereto, outlet means disposed in saideccentric means and said stator means, said inlet means cooperating witheach of said passages as said rotor means rotates to transmit saidcooling fluid therethrough to cool one lobe and to partially heat theadjacent lobe, said outlet means cooperating with each of said passagesas said rotor means rotates to receive the cooling fluid after coolingthe one lobe and partially heating the adjacent lobe; and meansconnected between said inlet means and outlet means to supply andreceive the cooling fluid.

2. A rotary engine according to claim 1, wherein said arms are disposedin diametrical relationship and each arm is divided into two halves onehaving an opening and one being closed.

3. A rotary engine according to claim 1, wherein said arms are disposedin diametrical relationship and each engage said walls at the junctionof two lobes.

4. A rotary engine according to claim 3, wherein reinforcing meansextend from said hub member to said inner wall intermediate said armsand at the junction of, two other lobes to provide reinforcement to saidrotor means.

5. A rotary engine according to claim 1, wherein said supplying andreceiving means includes pump means connected between said inlet andoutlet means.

6. A rotary engine according to claim 5, wherein cooling means areconnected between said pump means and said outlet means to receive thecooling fluid therefrom and to cool same prior to being transmitted tosaid pump means.

Fraser May 25, 1909 Froede et al. July 3, 1962

1. A ROTARY ENGINE COMPRISING STATOR MEANS HAVING A PLURALITY OFCHAMBERS DISPOSED THEREAROUND AND INTERNALLY THEREOF, ECCENTRIC MEANSDISPOSED WITHIN SAID STATOR MEANS AND COAXIALLY THEREWITH, ROTOR MEANSHAVING A PLURALITY OF LOBES ROTATABLY MOUNTED ON SAID ECCENTRIC MEANS,SAID LOBES COOPERATING WITH SAID CHAMBERS AS SAID ROTOR MEANS ROTATES;SAID ROTOR MEANS INCLUDING AN OUTER WALL AND AN INNER WALL DEFINING ASUBSTANTIALLY CONSTANT WIDTH ANNULAR SPACE THEREBETWEEN, A HUB MEMBERENGAGING SAID ECCENTRIC MEANS, ARMS EXTENDING FROM SAID HUB MEMBER TOSAID WALLS THEREBY FORMING WITH SAID ANNULAR SPACE TWO CONTINUOUSPASSAGES; INLET MEANS DISPOSED IN SAID STATOR MEANS AND SAID ECCENTRICMEANS FOR SUPPLYING COOLING FLUID THERE-